Plaster building board



June 8 1926. 1,588,058

J. SCHUMACHER PLASTER BUILDING BOARD Filed July 14, 1924 2 Sheets-Sheet 1 June 8 1926.

1,588,058 J. SCHUMACHER PLASTER BUILDING- BOARD Filed July 14, 1924 28heets-Sheet 2 fivenfor Patented June 8, 1926.

UNITED STATES J'OHN SCHUMACHER, OF LOS ANGELES, CALIFORNIA.

PLASTER BUILDING BOARD.

Application filed July 14, 1924. Serial No. 725,901.

This invention relates to a plaster board or the like and to the method of forming the I same. The present invention appertains more especially to that class of plaster board having a plaster board and pliable fibrous sheets covering the same.

Such board is subject to rough handling and during its life is subject to strains at the edges whereby it may break and chip. The primary object of this invention is to provide an article and method of producing the same, wherein the finished product consists of a plaster board having reinforces of pliable material embedded in and bound to the plaster at the edges.

The product and method'of manufacture are clearly set forth in the following description, reference being had to the accompanying drawings, wherein:

Fig. 1 is an enlarged cross-sectional view of a fragment of a board'in its initial form showing the edge thereof before trimming; Fig. 2 is a perspective view of a fragn'ient of the board shown in Fig. 1 after it has been trimmed; Fig. 3 is a cross-sectional view of a fragment of a board before trimming and disclosing a variation of the structure shown in Figs. 1 and 2; Fig. 4 is a perspective view of the finished board of the type shown in Fig. 3; Fig. 5 is a cross-sectional view of a fragment of a board initially of a different formation which is finally completed to produce the board shown in Fig. 4; Figs. 6, 7, 8 and 10 are different species of board in their initially formed state before trimming; and Fig. 9 is the finished board of the species shown in Fig. 7.

The plaster bgard herein illustrated is in its general formation of the well known type consisting of a relatively thin layer of plaster interposed between covering sheets preferably of paper. In its manufacture, the wet plastic material is fed between the sheets of paper and cut into lengths of convenient size for handling and finally dried. In each of the figures, the cementitious body is indicated by 11 and is shown interposed be tween a top covering sheet 12 of paper or other fibrous material, and a bottom covering sheet 13. The terms top and bottom covering sheets are used merely for purposes of convenience, inasmuch, as the oard is alike on both sides. Broadly each species of board illustrated herein is the same, except for the reinforces which extend along the edges.

Referring more particularly to Fig. 1, the top sheet 12 is of-a greater width than the bottom sheet and during the formation and advance of the board, the top sheet 12 is turned inwardly at the edges as indicated by 14 so as to provide a strip of reinforcement extending. along the side edge. After delivery from the formation devices, the

board is trimmed by a saw or any other suitable trimming tool along the dotted line 15 of Fig. 1. This produces the finished product shown in Fig. 2' of the drawing The covering sheet is of a material which will form a bond with the plaster. For this reason bending of the board at the edges will not separate the reinforce from the body of the plaster. A unitary structure is thus formed at the edges thereby strengthening the same without affecting the pliability.

Referring more particularly to Figs. 3 and l, the covering sheets both top'and bottom are made of a width greater than the initially formed board. The top covering sheet is turned inwardly and embedded in the plaster body as indicated by 16. Similarly the bottom covering sheet 13 is turned inwardly and embedded in the plaster board asindicated by 17.. The board is then trimmed along the line 18 producing the finished board shown in Fig. 4. This board only differs from that shown in F ig. 2 by reason of having two parallel strips of reinforcement bound plaster. r

The initially formed board shown in Fig. 5 varies in its formation from that heretofore described by en'ibedding in the edge of the board a U-shaped reinforce having legs 19 and, 20 directed into the plaster and a 'uncture 21 flush with the edge. The initially formed board is then trimmed along the line 22 producing thereby the same product as is shownin Fig. 4.

Fig. 6 shows a board initially formed by turning in the top and bottom covering sheets 12 and 13 and also inserting a U- shaped strip 23 of paper or the like. The edge of the board is then trimmed by cutting along the line 24, thereby roducing a plaster board having four para lel reinforce strips.

The structure shown in Figs. 7 and 9 are similar'to that shown in Fig. 6. However, the marginal edges of the covering sheets 12 and 13 are turned inwardly at an'an le, as indicated by 25 and 26. The U memlier 27 is inserted at the center of the edge, and

the board is then trimmed along the line 28 to form a finished board shown in Fig. 9.

The structure of the board shown in Fig. 8 is obvious from an inspection of the drawing. A single reinforce strip 29 is embedded in the edge of the board, and the latter then trimmed alon the line 30. The board shown in Fig. 10 is ormed of the same elements as that shown in Fig. 5, the U member 31 comprising the reinforce is turned in the opposite direction so that the legs are directed out- Wardly. The board is then trimmed along the line 32. ()ther variations embodying the inventive idea will be obvious to those 2. The method of making an edge rein forced plaster board comprisin applying a covering sheet to a plastic b0 y turning a marginal edgeof said covering sheet into the edge of said plastic body and trimming such reinforced edge of the green board.

3. The method of making an edge reinforced plaster board comprising applying covering sheets to a plaster body, turning marginal portions of said covering sheets into said plastic body, inserting longitudinally of said board, reinforcement strips at the edges thereof,- and trimming the edges of the green board so formed.

4. The method of making an edge reinforced plasterboard comprising applying covering sheets to a plastic body, turning marginal portions of said coverin sheets into said plastic body and trimming the edges of the green board so formed.

In Witness that I claim the foregoing I have hereunto subscribed my name this 30th day of June, 1924.

JOHN SCHUMACHER. 

